Tutorial: Moodle VPL -- A Multi-File Java Program with Data File

--D. Thiebaut (talk) 15:23, 13 June 2014 (EDT)

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Moodle VPL Tutorials

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This tutorial builds on the first one in the series, which should be done first, as the present tutorial skips some steps. This tutorial generates a VPL activity that allows automatic evaluation of a Java program with 2 classes stored in 2 files. The application gets its input from a data file. The evaluation tests the program with 3 different data files.

Setup

• Moodle Version 2.7 + (Build: 20140529)
• VPL Version 3.0.1
• For details on how Moodle and VPL were installed, go to this page.

VPL Activity Description

Java Test 2: Two Classes and One Data File

Due date: Tuesday, 21 June 2016, 8:00 PM
Requested files: Main.java, SortedList.java, data.txt (Download)
Type of work: Individual work
Grade settings: Maximum grade: 100
Run: Yes Evaluate: Yes
Automatic grade: Yes

Requested files

data.txt

    3
    4
    5
    1
    10
    11
    11
    -1
    100
    3
    9
    110  

Execution files

vpl_run.sh

#! /bin/bash
  
cat > vpl_execution << 'EOF'
#! /bin/bash
javac -J-Xmx128m *.java 
java Main
  
EOF
  
chmod +x vpl_execution

vpl_debug.sh

File not needed

vpl_evaluate.sh

File not needed

vpl_evaluate.cases

case = Test 1
input = data.txt
output = "File name? min = -1
max = 110
"

case = Test 2
input = data1.txt
output = "File name? min = 1
max = 1
"
case = Test 3
input = data2.txt
output = "File name? Empty array
min undefined
max undefined
"
case = Test 4
input = data3.txt
output = "File name? min = 10
max = 10
"

data1.txt

1
1
1
1
1

data2.txt

Empty file (does not contain any number)

data3.txt

10

Advanced Settings/Files to Keep

• Make sure to click on all the data files you are adding to the module, so that they will be sent to the jail server for testing the student program.

Testing

• Enter the following code in the Edit windows of the Test activity area. Pick the appropriate file name for the given code.

// Main.java
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;

import java.util.Scanner;

public class Main {
	
	
	public static void main(String[] args) {
		BufferedReader br = null;
		String sCurrentLine = null;
		SortedList array = new SortedList();
		
		Scanner keyboard = new Scanner( System.in );
		System.out.print("File name? ");
		String fileName  = keyboard.next().trim();

		try {
			br = new BufferedReader( new FileReader( fileName ) );
			while ((sCurrentLine = br.readLine()) != null) {
				int x = Integer.parseInt( sCurrentLine.trim() );
				array.add( x );
			}
			
		} catch (IOException e) {
			//e.printStackTrace();
			System.err.println( "Could not find file" );
			return;
			
		} finally {
			try {
				if (br != null)
					br.close();
			} catch (IOException ex) {
				//ex.printStackTrace();
				return;
			}
		}
		
		if ( array.isEmpty() ) {
			System.out.println( "Empty array" );
			System.out.println( "min undefined" );
			System.out.println( "max undefined" );
			return;
		}
		int max = array.getLast();
		int min = array.getFirst();
		System.out.println( "min = " + min );
		System.out.println( "max = " + max );
	}
}

• Second program file:

import java.util.ArrayList;
import java.util.Collections;


public class SortedList {
	
	ArrayList<Integer> array = null;
	
	SortedList() {
		array = new ArrayList<Integer>();
	}
	
	public void add( int x ) {
		array.add( x );
		Collections.sort( array );
	}
	
	public boolean isEmpty() {
		return array.isEmpty();
	}
	
	public int getFirst( ) {
		return array.get( 0 );
	}
	
	public int getLast( ) {
		return array.get( array.size() - 1 );
	}
}

• Click on Save, then Run and verify that you get a correct output in the terminal window.
• Click on Evaluate and verify that you get 100/100 for the 4 tests.

This concludes this tutorial